Leicester have abandoned plans to take an appeal over Adrien Silva's registration to the Court of Arbitration to Sport after FIFA blocked an expedited process.
The club had hoped for a quick hearing so Silva could play before next year but world football's governing body refused to agree.
Leicester are understood to be seething at the development, having found forensic IT evidence that documents were lodged with FIFA before the deadline of the summer window.
But FIFA's stance means midfielder Silva, a £22million signing from Sporting Lisbon, cannot be registered for Leicester until January 1.